To change timezone for your web application, navigate to config/app.php file and look for following code,

/*
|--------------------------------------------------------------------------
| Application Timezone
|--------------------------------------------------------------------------
|
| Here you may specify the default timezone for your application, which
| will be used by the PHP date and date-time functions. We have gone
| ahead and set this to a sensible default for you out of the box.
|
*/
'timezone' => 'UTC',

And replace UTC with your own timezone. For example you can change it to something like,